1. Field of the Invention
The present invention relates generally to the field of computer-based imaging, and, more particularly, to detecting spherical and ellipsoidal objects from an image.
2. Description of the Related Art
A number of image-based computer-aided diagnostic (“CAD”) tools aim to help physicians detect spherical and ellipsoidal structures in a large set of image slices. In a chest image, for example, a physician may be interested in detecting nodules, which appear as white spheres or half-spheres inside the dark lung region. In a colon image, for another example, a physician may be interested in detecting polyps, which appear as spherical and hemi-spherical protruding structures attached to the colon. In a vessel image, for another example, a physician may be interested in detecting aneurysms, which appear as spherical protruding structures out of the vessel surface. Physicians may desire to detect any of a variety of other structures present in the anatomy. These structures may include, but are not limited to, various types of cysts, polyps in the bladder, hemangiomas in the liver, and the like.
Current approaches for detecting spherical or partially spherical structures from a 3D image generally divide the image into a number of 2D planes. Circular structures or bumps are then detected in the number of planes, which are oriented in a number of directions that span the entire image. Information collected from the number of planes can be combined into a 3D rendering.
Further, the original volumetric data may be pre-processed, e.g., to enhance the overall outcome of the process, or to find spherical objects in another representation of the same image after some transform. However, such pre-processing may take time and make assumptions that are not robust or consistently valid, resulting in performance failures.